Prader-Willi syndrome is a rare genetic disorder in which 7 genes on chromosome 15 are deleted/unexpressed on the paternal chromosome. Usually, these genes on the maternal copy is imprinted, and thus silent, thus relying only on the paternal copy.

• Low muscle tone
• Short stature
• Incomplete sexual development
• Cognitive disabilities
• Problem behaviors
• Chronic feeling of hunger that can lead to excessive eating and life-threatening obesity

• Early intervention can reduce obesity to be similar to the typical population
• Behavioral therapy